Surgical aid to orthodontics.pdf - SURGICAL AIDS TO...

This preview shows page 1 out of 92 pages.

Unformatted text preview: SURGICAL AIDS TO ORTHODONTICS DR LILIAN AHAJI INTRODUCTION • Orthodontics is a specialty of dentistry that deals with diagnosis, prevention and correction of mal-positioned teeth and abnormal join relation. • It can also focus on modifying facial growth, known as dento-facial orthopaedics or orthognathics. • Some orthodontic procedures require surgical assistance unerupted or impacted teeth are the most common reason for surgical intervention but occasionally, soft-tissues surgery is indicated. • Some cases cannot be treated simply by orthodontics alone and require surgery to the mandible and / or maxilla-orthognathic surgery osteotomies such cases require a combined approach and careful planning to ensure optimal results. • Although treatment of facial deformity is not within the scope of general dentistry, the dentist has an essential role to play in the general dental care of such patients. • This is especially important in cleft deformity and their relatives. THE ORTHODONTIC/ORAL SURGERY INTERFACE • Oral and maxillofacial surgery, in the context of this lecture includes a wide spectrum of procedures ranging from the removal and exposure of unerupted teeth to bi-maxillary osteotomies. • In planning these procedures, it is essential to involves the specialist orthodontist and the patients themselves from an early stage. • Surgery in the orthodontic patient will often be an integral part of a protracted treatment programme, which may, especially in the case of adult fixed appliance therapy, take 2years or more to complete. • It is essential, at the planning stage of the dentoalveolar surgery, that the patients understand and are willing to comply with the extent and duration of the proposed therapy. • The extraction of healthy, normal, fully erupted teeth is frequently an essential part an over all orthodontic treatment plan. • Further, during a course of regulation treatment surgery may also be employed to deal with unerupted, semi-erupted or misplaced, super numerary teeth, dilacerated and submerged teeth and persistent abnormal frenum labia. • These procedures seldom present any problems if a systematic approach is employed. • Prior to surgery being undertaken, a complete diagnosis, assessment and treatment plan must be made, not just a surgical plan, not just an orthodontic plan, but a complete dental treatment plan which embraces all the conservative, periodontal, prosthetic, orthodontic and surgical treatment required. • A carious exposure of the pulp may make radical revision of an orthodontic treatment plan essential and it is preferable to know about it before the die is cast by surgical intervention, vitality testing of adjacent teeth, especially upper lateral incisors, prior surgery should be undertaken as a routine procedure. • It is better to discover that an unerupted canine is related to pulp less lateral incisor of dens invaginations type before surgery than after operation • Proper treatment planning enables any necessary preliminary orthodontic required treatment to be performed before surgery whilst any extra actions which are required as part of the treatment plan can often be performed under the same anaesthetics. • These comments should not be interpreted as a plea for procrastination, for although surgery performed in conjunction with orthodontic treatment may be undertaken at anytime, experience shows that it is most successful when performed during the eruption phase of any involved displaced tooth. • The importance of early recognition and correct diagnosis of any abnormality involving the eruption of teeth cannot be over emphasized. • The interface between oral surgery and orthodontics is difficulty to define accurately but relates to those patients whose treatment decisions lie with both specialities. • There will always be cases which choices must be made to recommend orthodontics done, surgery alone, surgery alone, combination of the two or whether no intervention should be recommended. • DECISION MAKING IN COMPLEX CASES REQUIRES A COMBINATION OF SKILL AND EXPERIENCE AND MUST BE TAKEN WITH THE PATIENTS BEST INTERESTS AS THE FUNDAMENTAL STARTING POINT. MANAGEMENT OF UNERUPTED AND IMPACTED TEETH • Nowhere is the practice of dentoalveolar surgery and orthodontics more closely related than in the management of unerupted and impacted teeth. • The teeth most frequently affected by failure of eruption are generally the last to erupt in a particular series wisdom teeth, canines and second premolar teeth. ASSESSMENT OF UNERUPTED TEETH Clinical • In orthodontic cases, it is unusual for patients to suffer any symptoms from unerupted teeth, they are far more frequently noted after clinical examination or as incidental radiographic findings. • Careful monitoring of the eruption of the dentition is essential and the general dental practitioner is best equipped to perform this task. • The combined oral surgery and orthodontic treatment options for unerupted teeth are threefolds: extraction, exposure-orthodontics and auto transplantation (most frequently of canines) unerupted teeth may be left in situ. • The auto transplantation of teeth is performed far less frequently than it was in the past due to unpredictable outcome and the reliability of osteointegrated implants and adhesive bridgework. • The timing of extractions or exposure is dependent on the age of the patient and the stage of development of the dentition. • The principal treatment decision in the management of unerupted teeth is whether to extract. • In general terms, the rationale for removal of unerupted/mal-positioned teeth resembles that for wisdom teeth. The principal indications for extraction are: • Space creation • Pathology associated with the unerupted tooth (e.g. caries or cyst formation) • Evidence or risk of root resorption of adjacent teeth. • Malformation of the crown and / or root of the unerupted tooth which would impede eruption or render the tooth useless cosmetically and functionally if it were to erupt. • There is some evidence that timely extraction of deciduous teeth may prevent later impaction particularly in the case of upper canines. The surgical and radiographic assessment of unerupted teeth in orthodontic cases is based upon determining; • The position of the teeth • Factors which may impede conventional surgical removal (or indeed eruption), such as dilaceration, hooked roots, proximity to adjacent teeth. • The proximity of the teeth to important anatomical structures of the mental nerve, maxillary sinus or adjacent unerupted teeth. • Whilst the crowns of the teeth are frequently in communication with the oral density, even where the teeth are not directly visible clinical examination and palpation of the alveolus will often demonstrate a bulbosity associated with crowns of unerupted teeth, thereby giving an indication of their position. • Additionally the inclination of adjacent teeth may be give some important due to the position of the crown of an unerupted. • Radiographic analysis, however is essential to determine the apex position, morphology and pathology associated with unerupted teeth. Radiographic • Radiographic assessment of the unerupted tooth will provide several valuable pieces of information in planning its management : stage of tooth development, crown / root morphology and angulation and the presence or absence of local disease. • Most orthodontic assessment will includes an orthopantomogram (OPT) and a lateral cephalometric views are essential, however, for the management of unerupted maxillary anterior teeth due to the poor definition of the OPT in this region. • In this situation the OPT will usually be supplemented with periapical and / or upper anterior occlusal films. • The use of the parallax analysis in which two periapical views of the same area are taken from different angles can be useful in determining whether the impacted teeth are buccal or palatal and therefore in planning the surgical approach to the teeth. • In radiographic analysis the stage of tooth development must also be carefully considered because it is appropriate to expose teeth whose development is incomplete. • Periapical films:- These reveal the condition of teeth adjacent to the buried tooth together with the size, shape, and root pattern of the unerupted tooth. • The presence of cysts, odontomes, or supper-numerary teeth can also be detected in a periapical film, which may also give some indication of the relationship between the buried tooth and the adjacent erupted teeth in the vertical plane. • Whilst the relative definition and radiopacity of the crown may assist in the determination of the tooth position, a more reliable estimate can be made by use of the so-called parallax method. • Parallax technique : In this technique a periapical radiograph of the area is taken and the x-ray tube is then moved in either a mesial or distal direction before a second periapical films is taken. • The two radiographs are then compared and if the buried tooth is seen to move in the same direction as the x-ray tube it is lying palatally to the standing teeth, whilst if it moves in the opposite direction, it is lying on the labial side of the standing teeth. EXPOSURE OF THE UNERUPTED TOOTH SURGICALLY • The decision to expose or not, however, is principally based in three factors: • The angulation of the unerupted tooth • The depth of impaction • The relationship to other tooth. In general terms there are four treatment options: • Extraction • Auto transplantation • Simple exposure • Exposure with the application of direct mechanical force to the teeth. • The objective of exposing an unerupted tooth is to move it into a good functional and aesthetic position. • In assessing teeth for exposure one of the prime considerations is the available space into which the tooth can erupt. • This may be estimated by comparing the crown width of the unerupted tooth with the available space, either directly from the radiograph ( with reference to the magnification in the system) or by measurement of the crown width of the contra lateral corresponding tooth. • A decision must be taken as to whether they should be : ▪ left in situ ▪ Exposed ▪ Transplanted ▪ Removed SURGICAL TECHNIQUES • Exposure at it is simplest consists of removal of the soft tissues overlying the crown of an unerupted tooth under local anaesthetic. • The exposure of teeth in this fashion has major disadvantages: -Removal of the attached keratinized gingival -The possibility of re-epithelisation of the healing of the defect before the tooth, has time to erupt. -Loss of an acceptable mucogingival contour. • Attempts should be made retain the keratinized tissues by employing displacement of the attached gingiva with apically or occasionally, laterally repositioned flaps. • The apically repositioned flap retains the muco-gingival collar around the tooth and is displaced apically and sutured into place. • The bunched gingiva will model as wound healing occurs. • If the tooth is unaligned, a bracket and gold chain may be etched to the canine to direct its erupted path appropriately. • Although simple exposure is satisfactory for superficially placed teeth situated close to the surface and impacted in soft tissues alone, most unerupted teeth are located more than 3-4mis from the oral mucosal surface and the crown can not be seen completely after raising a flap. • As impaction of unerupted teeth usually involves local tissues as well as soft tissues, all bone covering the tip of the crown as far as the maximum width of the tooth should be carefully removed. • If the tooth is superficial and covered by thin bone this can often be undertaken using a scalped blade. • where bone coverage of the unerupted tooth is more extensive, a small rose head bar or handheld chisel may be used to clear overlying bone from the crown. • Extreme caution must be taken to avoid damage to the tooth crown and the roots of the adjacent teeth unnecessary removal of bone should also be avoided. • Whilst soft and hard tissues exposure of unerupted tooth is in some instance successful, most commonly (and especially in the case of deeply impacted teeth) the created surgical defect will become re-reepithelialised, if the patency is not maintained. • The defect is therefore, packed with an antiseptic gauze • Dressing or a fashioner cement bonded to the tooth crown in order to inhibit contraction and re-epithelisation. • Post operative antibiotics are seldom indicated unless there is known increased risk of wound infection. SURGICAL EXPOSURE OF THE TEETH FOR ORTHODONTIC REASONS Canines: • A technique which has been successfully employed to expose a canine for orthodontic purposes on many occasions illustrated. • After the radiographs have been carefully examined a cruciform incision is made with its centre over the estimated position of the crown of the buried tooth. • The four triangular flap are raised and after the actual position of the crown has been verified the appropriate extensions are made to the incisions and the resulting flaps excised. • Palatal vessels can usually be controlled by pressure, and the insertion of a starry suture is seldom required. • At the end of the operation the crown of the tooth will left lying in a saucer-shaped bony cavity and a pack is inserted to prevent the soft tissues growing over the exposed tooth. • If the soft tissues are removed in the manner described, the margins of the muco-periosteal defect remain firmly attached to bone and the insertion of the pack is facilitated. • whilst if a flap has been raised and replaced, the pack tend to spread out between the surface of the bone and the periosteum when pressure is applied. • By use of hand pressure on a chop chisel, or hand gauge, bone is removed so as expose the tip of the cusp, the cingulum, and the greatest mesial and distal convexities of the crown. • Surrounding bone is carefully excised in a similar fashion to saucerize the resultant bony cavity as far as this is practicable without the risk of damaging either adjacent standing teeth or their supporting tissues. • It is very easy to damage the tooth being exposed if either bars or mallets are employed during bone removal and so it is wise to avoid using these instruments for this purpose if it is practicable to do so. • Some orthodontists believe that removal of the labial muco-periosteum and bone during the surgical exposure of a tooth may result in the cervical margin of such a tooth being at a higher level than that of its neighbours when eruption is complete. • Other authorities state that this finding is due to the anterior position of the affected tooth in the bone and claim that the condition resolves as the passive phase eruption i.e., the rolling back of the soft tissue process. • Nevertheless, care should be taken to keep the removal of labial muco-periosteum and bone to the minimum amount which is required to expose the tooth satisfactorily. • The resultant cavity is then tightly packed with wisps of cotton-wool impregnated with a paste of zinc oxide and oil of cloves, which is built up to form a pack which is left in situ for 10-14 days. • Small pieces of the packing material should be inserted into the most inaccessible areas first and a mattress suture may be required to aid, the relation of the in situ. • Most correctly assessed and adequately exposed canines erupt without the insertion of pins, inlays, or the fitting of celluloid crown forms or stainless – steel bands. • It is a widely held opinion that the application of traction by such means may be followed by either failure of the tooth to erupt or pulpal death or both. • However as these techniques are usually employed in the treatment of badly placed canines or in those cases in which treatment is commenced after the normal time of eruption, such opinions are a matter of debate. • If traction is to be employed, it is best applied by the use of a bracket cemented to the crown of the canines after the tooth has been acid etched. • The eruption of an exposed canine can be aided by cutting away the bone which obstructs the path of movement, distobuccal bone in the case of a palatally situated canine, to form an eruption channel. • If this is practicable. • Although adequately exposed canine usually erupt, many orthodontists are tending to request surgical exposure less frequently, perhaps because the end result do not fortify the amount of treatment required in many cases. • An alternative treatment involving removal of buried canine at an early age gives excellent results in suitably selected cases. Incisors • The surgical exposure of an unerupted incisor tooth is performed in a Similar fashion to that described above ,care being taken to expose the entire incisal edge, cingulum, and mesial and distal convexities of the buried tooth. • When incisors are palpable above the reflection of the mucous membrane they may be exposed with ease by incising the mucosa. • This, however, may give a shallow labial sulcus with a deficiency of attached muco-periosteum. • If the gum is incised well on the palatal side of the buried tooth and the resultant muco-periosteal flap is widely undermined and rotated forwards and upwards to line a labial sulcus a better result is obtained. • By using an apically repositioned flap in this manner the amount of attached labial muco-periosteum is increased and gingival health is preserved . Cheek teeth • When exposing a cheek tooth the bone and soft tissues should be cleared from the cusps, the occlusal surface, and the crown down to and including the greater convexity of the tooth. • This leaves the cervical portion of the anatomical crown surrounded by a collar of soft tissues and thin bone, which should be packed away from the tooth with an annular pack of zinc oxide and oil of cloves on cotton-wool. • The patient is instructed to keep the site of exposure clean by using hot saline mouth baths and the pack is removed 2weeks after operation. • Surgical exposure of unerupted teeth followed by any necessary orthodontics treatment is a very successful method of method of bringing teeth into occlusion. • The optimum age for such treatment is from 12 to 14 years and it is seldom successful when used in patients over 17years of age. Abnormal frenum labia: • In some cases the upper central incisors are separated by a diastema, through which the labial frenum passes to gain attachment to the incisive papilla, which is seen to blanch when the lip, and frenum are tensed. • A periapical radiograph often reveals a marked aid line suture in these cases. • In the majority of patients the space between the central incisors closes the permanent canines erupt but an orthodontist may ask for the removal of the labial frenum as an adjunct to his appliance therapy. • There is some evidences that in patients in whom there is a tendency towards spacing of the teeth, such as those with small teeth set in large jaw, the upper labial frenum may interfere with the formation of transeptal gingival, cervical and alveolar crest bundles of the periodontal ligament between the central incisors. • A midline diastema may also be associated with the presence diminutive lateral incisors or a supernumerary tooth in the midline or both on other occasions the lateral incisors are absent or an occlusal abnormality due to mal position of the lower incisors is present. • There are great differences of opinion between orthodontists concerning the relationship of the frenum to the diastema and the indication and contra-indication for surgical treatment. • Nevertheless, if the operation is performed at the optimum time correctly assessed cases, the result are most gratifying. • It is usual to delay frenectomy until the eruption of the lateral incisors is complete and the diastema has failed to close naturally. The operation can be performed either before or after the central incisors have been approximated by applian...
View Full Document

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture